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Sub Delta Variant (AY.4.2)
- The variant currently accounts for 8% of sequenced coronavirus cases in the UK.
- The variant could be 10 percent more transmissible than the most common Delta variant in the UK.
- It carries two characteristic mutations in the spike, Y145H and A222V.
The Delta Plus Variant (AY.1)
- The Delta plus variant was first found in India in April, 2021
- The variant has also been found in nine other countries: USA, UK, Portugal, Switzerland, Japan, Poland, Nepal, Russia and China.
- The variant contains an additional mutation called K417N on the spike protein. It has been suggested that this change slightly reduces binding affinity to ACE2.
- Currently, it is uncertain whether this additional mutation is causing enhanced severity, transmissibility, and immune evasion of this Delta Plus variant compared to the Delta variant.
- A recent study showed that the hamsters infected with B.1.617.1 demonstrated increased body weight loss, higher viral load in lungs and pronounced lung lesions as compared to B.1 variant. Further studies will be required to confirm its disease severity.
- It is not clear whether this variant enhances the disease severity.
- Use of a live virus assay showed that the B.1.617.1 variant is 6.8-fold more resistant to neutralization by sera from COVID-19 convalescent and Moderna and Pfizer vaccinated individuals.
- Despite this, a majority of the sera from convalescent individuals and all sera from vaccinated individuals were still able to neutralize the B.1.617.1 variant.
- Protective immunity by the mRNA vaccines tested here are likely retained against the B.1.617.1 variant. This needs to be further evaluated by evaluating clinical data from vaccinated individuals.
- In the U.K. trial, efficacy of 2-dose Pfizer vaccine against this variant was 87.9% (93.4% against B.1.1.7); 2-dose AstraZeneca showed 59.8% efficacy against this variant and 66.1% against B.1.1.7.
- Effectiveness of COVID-19 vaccines against the B.1.617.2 variant.
Medrxiv, May 24, 2021
- Infection and vaccine-induced neutralizing antibody responses to the SARS-CoV-2 B.1.617.1 variant
BioRxiv, May 10, 2021
- SARS-CoV-2 variant B.1.617 is resistant to Bamlanivimab and evades antibodies induced by infection and vaccination
Biorxiv, May 5, 2021
- SARS CoV-2 variant B.1.617.1 is highly pathogenic in hamsters than B.1 variant
Biorxiv, May 5, 2021
- Emergence in late 2020 of multiple lineages of SARS-CoV-2 Spike protein variants affecting amino acid position 677
MedRxiv, February 14, 2021